Method of solvent recovery



R. C. ALLEN METHOD OE SOLVENT RECOVERY 2 Sheets-Sheet l Filed March 3, 1921 #lill M/xEa pas wo vAPoz/ CNAM [BED ADI P'LIDN GMM slib l l pE---wamen/rg PUNP "SIM/Mbo@ f//m Tn WA a Tl jan,

y Rc. ALLEN METHOD OF SOLVENT RECOVERY Filed Maron 1921 2 sheets-sheet 2 Patented Jan. 13, 1925, p i p i .I i UNITED STATES PATENT OFFICE.v

ROBERT c. ALLEN, or LAKEWOOD, Onro, assreNoa 'ro HENRY L. DOHEErY a OOM- PANY, or NEW YORK, N. Y.

METHOD OF SOLVENT RECOVERY.

Application filed. March 3, 1921. Serial No. 449,551.

u To all whom it may concern: heated steam being the' agent used to effect Be itknown thatI, ROBERT C. ALLEN, a such extraction, provision is also made for citizen f the United States, and a resident the economical use of the steam, sothat the of Lakewood, county of Cuyahoga, and extraction may be accomplished with a minil State of Ohio, have invented a new and usemum expenditure of power. 60 ful Improvement in Methods of Solvent Re- To the accomplishment of the foregoing covery, of which the following is a speci and related ends, the invention, then, concation, the principle of the invention being ssts of the means and steps hereinafter fully L herein explained and the best mode in which described and particularly pointed out in l have contemplated applying that prin the claims, the annexed drawings and the 65 ciple, so as to distinguish it from other infollowing description setting forth in detail ventions. certain means and one mode of carrying out The present improved method and appa the invention, such disclosed means and ratus, relating, as indicated, to solvent remode illustrating, however, but one of varicovery, should be understood as compreous ways in which the principle of the in- 70 bending generally the extraction or adsorpvention may be used. tion of vapors, and particularly of the va- In said annexed drawings pors of volatile hydrocarbons from adinix- Fig. 1 is a diagram showing, after the tures thereof with air or other gases. Thus fashion of a flow sheet, the arrangement of 'in various manufacturing processes, involvapparatus and successive steps under the 75 ing the use of benzene and other similar solprocess exemplified in the operation of -vent agents, considerable quantities of such such apparatus; Figs. 2 and 2a show a agents ordinarily are converted into vapor central vertical cross-section of the prinform and so lost. It has also been found cipal element of such apparatus which conthat a considerable quantity of naphtha and sists of a vertical column divided into secso high test gasoline are present in the form tions forming an adsorption chamber, re- I' of vapors in commercial natural gas, and covcry chamber, and cooling and discharge i the recovery and liquefaction of such vapors chamber; Fig.' 3 is a transverse section of has become an importantphase of the insuch apparatus taken on the plane indicated dustry. by the line 3-3, Fig. 2; Fig. 4 is a side elee5 The availability of solid, more or less pulvational view of a detail of piping shown verulent adsorbent materials for use in the in plan vin Fig. 3; Fig. 5 is a broken section recovery of vapors of the characterijust recorresponding with that of Fig. 2, showing ferred CO iS knOWll, fOTeInOSt amOng SUCh a modified construction of recovery chammaterials perhaps being the so-called acber; Fig. 6 is a transverse section; and Fig. 90 tivated carbon or charcoal, developed dur- 6a an enlarged transverse section of such ing the recent war for use in gas masks, to modified construction, taken on the plane inremove from the atmosphere the poisonous ligated by the line 6 6, Fig. 5. gases used in chemical warfare. Another As indicated in connection with the gensueh material is silica gel, and a variety of eral description of the drawings, the central leSS active matel'ai BXS. element of the apparatus consists of a series The Object 0f the pleSent invention iS t0 of chambers through which the adsorbent provide a method and apparatus for recovery material is caused to pass in a downward diof vapors such as hereinbefore referred to rection under gravity. Thus referring to in a continuous 0r cyclic fashion, the ad- Fig. 1, such material passes from a storage 100 sorbent material being used over and over hopper 1 through the adsorption chamber 2 a ain without interrupting the operation. proper; thence through the recovery cham- A further object is to increase the efficiency ber 3; and finally to a chamber 4 in which of the recovery, both by insuring the subthe adsorbent material is cooled, and from stantially complete adsorption ofthe vapors which it is discharged or rather returned from the air or other gaseous medium with again to chamber 1 by means of suitable conwhich they may be admixed, and similar veying or elevating mechanism 5 which is complete extraction of the adsorbed vapors illustrated in diagrammatic fashion only in from the material, e. g. activated carbon, the drawings. It will be understood, how- 55 employed as the adsorbent agent. Superever, that such return of the adsorbent ma- 110 terial is preferably effected under cover, i. e. through a closed ductI or conduit, and since the particular means employed for the pur pose constitute no part of the invention` detaiied illustration has been omitted from the drawings.

The mixture of gases, including the vapor I to be recovered, is admitted for treatment in gasoline. so that a. proper rate of fiowv through the adsorption apparatus may be maintained and the treated gas supplied to the city mains under proper pressure.

The superheated steam employed in the recovery chamber is obtained from a suitable generator 10, and the resultant mixture of steam with recovered volatile product is conducted from the recovery chamber, through a vacuum pump as shown in. Fig. 1, to a condenser 11, the condensate thence passing to a separator 12. AThe coolingwater employed in the condenser is collected along` with that employed in the. cooling chamber 14, and used, so far as needed. in the steam generator 10, the excess going to waste,

The several chambers 2` 3 and 4, consist, as previously indicated, of successive sections of a continuous, vertically disposed chamber or passage, as shown in central vertical section in Figs. 2 and 2, such passage being designed to be more or less filled with a column of the particular adsorbent material employed in the process. Such passage or succession of chambers is preferably of the rectangular form in cross-section shown in Fig.v 3, the walls 15 consisting of metal plates or sheets suitably riveted or otherwise fastened together, and the pair of opposite Walls having the greater width being formed with perforations 1.6 for the passage of or steam transversely through the corresponding section of the passage which forms either the adsorption or recovery chamber, as the case may be. The walls that are thus perforated are also provided iuteriorly with a series of downwardly directed flanges that serve to shield the perfor-ations 16. and thus preventthe material from entering and clogging same, as will be readily understood.. The portions of the -wallsbet\\'een the se tions of the passage thus constituting the successive chambers 2, I and l. as well as the walls of chamber 4f itself, are iinperforate. The interposition of in--lined flanges 18 at the upper and lower ends` of sections 2 and 3, such flanges more closely constricting the passage than do flanges 17, serves to mark off these chambers and to leave therebetween an intermediate chamber 19 in which the accumulated material acts as a plug or seal to prevent the gases from either chamber 2 or 3 finding their way to the other such chamber.

The chamber as a matter of fact extends below the lower flanges 18, j ust referred to as defining the same, to providefa lower adsorption chamber 3a, which communicates directly with the cooling chamber si. A series of cooling coils 2f) through which water or like. cooling medium is circulated, serves to lower the temperature of the material to the desired point as it passes through said chamber 4 into a discharge hopper 21 where a rotary valve 22 or like device is employed to remove the material at the proper rate` while still keeping the lower end of chamber 4C sealed. As previously described. the material is then returned. by a suitable conveymg or elevating mechanism` to the upper end of the passage or succession of chambers. lfere it is received in a suitable feed hopper 2l from which it is transferred atl a rate corresponding with that of its discharge from chamber 4 by means of a suitable feed valve 25 to the storage chamber 1. Y.

Laterally adjacent the perforated sections of walls 15 that mark the extent of chamber are supplemental chambers 26 and 27 completely enclosing such perforated sections. The mixture of gas and vapor to be treated is received in said chamber 26, through a branched piping connection 28 (shown in de tail in Figs. 3 and 4), whereby such gases are distributed uniformly transversely` of such chamber, and further distribution thereof so as to insure an equal/pressure tlnfoughout the extent of the adjacent perforated wall 15 is' secured by interposing in the chamber a vertical partition wall 2f) having perforations 30 that are separated from each other by inwardly directed transversely disposed partitions 31.' The chamber 2T is likewise provided with a vertical partition wall 32 having perforations and a branched system of collector pipes (not separately shown) similar to piping 28 -is util-l ized to draw off the gases from'said chamber 27.

The perforated sections of Walls 15 that form a part of chamber 3 are similarly laterally enclosed by means of chambers 35 and 36, the construction of which is sub'- tantially identical with that of chambers 26 and 27, and so need not be described in detail. It will further be understood that branched distributor and, collector pipe, similar to piping 28,-is used to supply steam to and withdraw the same from chambers 35 and 36 respectively.

In Figs. 5 and 6 I show, by Way of modification, the substitution of screen Walls 37 for the flanges 17 that form a feature of chambers 2 and 3 in the first described construction. These screen Walls 37 are sup` teramo ported in suitably spaced relation from the perforated Walls 15, and consist of tightly strung horizontal and vertical Wires or rods 38 which are not interwoven but simply lie flat against each other, as best shown in Fig. 6, such rods being brazed or Welded together. It will be understood that the vertially disposed wires are the inner ones, which come in direct contact with the material. and so oppose the least resistance to the free movement of the material down- Wardly through the chamber.

In operation, a column of adsorbent material, such for example as activated charcoal, will be caused to continuously pass downwardly through chambers :2 and 3 in succession, such material being suitably cooled before it is admitted to said chamber 2. Simultaneously a continuous lloW or' the gaseous mixture that contains the vapors to be adsorbed is maintained through the portion of the column of material. lying in said chamber 2. The rate ot such gaseous flow being properly correlated with the rate of movement ot the adsorbent material, it is possible to obtain a maximum degree ot' extraction of the desired vapors, and at the same time a maximum charge in the adsorbent material. The treated gas thence passes from the apparatus, while the adsorbent material thuscharged passes from chamber Q through the intermediate chamber 19 into recovery chamber 3. Here the material meets with a transversely lowing stream of superheated steam, the tempera` ture of which is sufficiently high, and the rate of lloW so gauged, that by the time the material reaches the lower end of said chamber 3 substantially all of the adsorbed vapors will have been driven on and carried With the steam to the condenser 11. The material thus treed of its charge ot adsorbed vapors is then cooled in chamber 4 and returned to storage chamber 1 to repeat the cycle.

It should be explained that the flanges 18, particularly the lowermost ones, also function to alter the relative position et the particles composing the adsorbent ina-- terial, the latter being turned over more or less so as to expose all such particles to the same steam treatment. ln other Words, the action is to bring the interior of the column ot material beyond such flanges -18 into contact with the Walls ot the chamber Where the steam enters.

It should also be noted that my improved apparatus and process may be operated in the extraction phase only to remove adsorbed vaporizable matters from material derived from a source entirely Without such apparatus or process. rllhus, for example, alcohol may be reclaimed from dregs, or from ground crude drugs, that have been treated in a percolator to extract essential den oils or other ingredients. By allowing such material to pass my apparatus With the transverse passage of steam, such alcohol will be volatilized and carried oil with the steam to be condensed and recovered by fractional distillation.

Other modes of applying theprinciple ot' my invention may be employed instead of the one explained, change being made as regards the means and the steps herein disclosed, provided those stated by any of the following claims or their equivalents be emploved.

l therefore particularly point out and dis'- tinctly claim as my invention 1. ln a process for recovering vapors or gases from an admixture thereof with other gases, the step which consists in passing the the mixture of gases to be treated transversely through a moving column otl material capable ot a-dsorbing such vapors or gases. substantially as described.

Q. ln a process for recoveringvapors or gases from an admixture thereof with other gases, the steps which consist in passing the mixture of gases to be treated transversely through a moving column of adsorbent material at one point, and simultaneously treating such column at a point beyond such first point todrive ed any adsorbed vapors.

3, ln a process for recovering vapors or gases from an admixture thereof with other gases, the steps which consist in passing the mixture ot gases to be treated transversely through a moving column ot adsorbent vmaterial at one point, and simultaneously passing through such column at a point beyond such first point a medium capable of driving oli' any adsorbed vapors.

et. In a process for recovering vapors or gases from an admixture thereoi with other gases, the steps which consi?t in passing the mixture ol gases to b transversely through a movi ce ol3 adsorbent material at one 'l' and simultaneously passing steam r"hrmigh such column at a point beyond such lirst point.

In a process for recovering vapors or gases from an admixture thereor with other gases, the steps whichv consist in continuously circulating a body of granular, solid adsorbent material, passing" "a continuous current ot the gases to be treated through such material at one point in its circuit. passing through such material at another point a continuons current ot steam, and cooling such material at a point beyond such current of steam.

6. ln a process for recovering vapors or gases from an admixture thereof with other gases, the steps which consist in continun ously circulating a body of adsorbent material, passing a continuous current of the gases to be treated through such material at one point in its circuit, passing through such material at another point a continuous current of steam, passing water through suitable coils in contact with such material at a point beyond such current of steam, and using the resultant hot Water in the generation of such steam. f

7. In a process for recovering vapors or gases from an adinixture thereof with other gases, the steps which consist in continuously circulating a body of adsorbent material, passing a continuous current of the gases to be treated through such material at one point in its circuit, passing through such material at another point a continuous current of steam', condensing such steam and admixed vapors by contact with watercooled means, and using the resultant hotV water in the generation of such steam.

8. In 'a process for recovering vapors or gases from an admixture thereof with other gases, the step which consists in passing transversely through a moving column of adsorbent material containin a volatiliz-iv able ingredient a medium capa le of drivxngg i z5 9. In a process for recovering va ors or" off the latter.

gasesfrom an admixture thereof yWit other gases, the step which consists in passing steam transversely through a moving column of adsorbentf-,material containing a volatilizable ingredient, whereby the latter is driven olf.

l0. In a process for recovering vapors or gases from an admixture thereof with other`- Signed by me, this 1st ay of March, 1921.

. lROBERT C. ALLEN. 

